The present invention relates to an antiviral substance having, as the active component, a mixture of polysaccharides and cytokinin active substances primarily consisting of zeatin-related substances which are extracted from the nutrient medium and tissue-medium of Basidiomycetes such as Lentinus edodes and formulated as it is without fractionating into special fractions, and to a method of treating viral hepatitis.
It is well known that a virus is a filter-passing pathogen, is from 20.mu. to 60.mu. in size and smaller than rickettsia, is parasitic in organisms other than viruses, and can proliferate only in living cells.
Viruses are pathogens of such diseases as Japanese encephalitis, influenza and hepatitis in animals, and recently there has been proposed a theory that a virus may be a pathogen of cancer, in an important paper on "Mechanism of carcinogenisis" by Eiichi Soeda, a member of National Genetics Laboratory, appeared in "Nature" an English science magazine, dated Jan. 31, 1980. According to the paper, cancer is induced not by incubation of a carcinogenic virus, but by a hereditarily existing cancerous gene (a normal cell has a cancerous gene, and about 90% of persons may have it,) is excited by X-ray or some chemical substances (carcinogenic substances) to induce cancerous protein resembling mid-sized cancerous protein of a cancerous virus, which relates to carcinogenesis.
The present inventor has researched mycelia of Lentinus edodes, and accomplished many inventions as to the method of extracting pharmacologically active components contained in the mycelia, while the present inventor has found out that an active substance of the cytokinin system is contained in the extract of the mycelia and that its extract is effective on vegetable viruses.
The present invention is accomplished by developing the above findings further and it is surely the present inventor who discovered first the presence of cytokinin (zeatin, zeatin ribocide, etc.) in the extract of nutrient medium and tissue-medium of Lentinus edodes.
The present invention relates to an antiviral substance prepared by pure-culturing of mycelia of Lentinus edodes by solid or deep cultivation, heating or homogenizing them to extract the component of the mycelia and the component of the metobolite simultaneously from the aqueous solvent, and refining the extract by filtering, condensation or freeze-drying, and the manufacturing method thereof.
It has been already known that some polysaccharides have antiviral activities, and some inventions of polysaccharides from Basidiomycetes are partially published; the present inventor has observed the vegetable hormone produced by Basidiomycetes and confirmed it as a cytokinin active substance mainly consisting of a zeatin-related substance; moreover, the inventor has found out that a mixture of the polysaccharide contained in the nutrient medium and tissue-medium of Lentinus edodes and the said cytokinin active substance is very effective on viral hepatitis, and thus accomplished the present invention.
The polysaccharide derived from Basidiomycetes which has been studied by some workers is the one which a component of a fruiting body or a mycelium, but the substance produced by a mycelium, i.e., a metabolite is discarded as waste in the extracting process.
The present inventor has observed the substance produced by the said mycelium, which is the metabolite, and a partial decomposition product of lignin by the mycelium as well as the component of the mycelium, and accomplished the present invention.
In the present invention the active component includes not only the component of the mycelium but the component of the metabolite produced by the mycelium and the component contained in the partial decomposition product of lignin, and the present inventor considers the nitrogen-containing polysaccharide in the extract as one of the antiviral components: the polysaccharide is of a rather low molecular weight i.e., from 3000 to 10000. Taking the sugar composition and amino acid composition of the extract, the polysaccharide is not the one in the mycelium but the one in the metabolite produced by the mycelium. In addition, the polysaccharide is quite different from the polysaccharide coming from a fruiting body or mycelium and has structural components different from those of the latter. The partial decomposition product of lignin from the medium will of course have an antiviral activity.
These components seem to act to increase immunity as well as to prevent the viral infection: that is, an antiviral substance has contact with tissue protein to degenerate it and to stop the virus before it causes the disease and inactivate it. In the metabolite, cytokinin active substances of vegetable hormone such as zeatin and zeatin ribocide and the anticytokinin active substance analogous to abscisic acid are confirmed to be present, and they may contribute to control of DNA synthesis.
The antiviral substance of this invention is characterized by being obtained from the extract of the nutrient medium and tissue-medium of Lentinus edodes as it is, and is administered without fractionating into special fractions.